1. Field of the Invention
The present invention relates generally to bulk material feeders and, more particularly, to a divergent inlet that improves material flow from the supply downcomer to the horizontal conveyor of the feeder.
2. Discussion of Prior Art
Those ordinarily skilled in the art will appreciate that numerous processes involve conveying a mass or masses of solid particulate material (alternatively referred to as bulk material) along a path from one location to another. Moreover, the material flow path will often involve a transition from generally downward flow to substantially horizontal flow. For example, bulk material will commonly pass through a downcomer to a substantially horizontal conveyor, whereby the material is directed downwardly through the downcomer to the conveyor and then carried horizontally away from the downcomer by the conveyor. Such an arrangement is often designed to move the material along the path or, in some instances, control the volume-rate or mass-rate of flow of material along the path. In addition, the downcomer and horizontal conveyor are often collectively referred to as a bulk material feeder.
In any case, there are often problems associated with material flow through a bulk material feeder. For example, the material is often not transferred to the conveyor at a uniform rate, even though there is a consistent rate of material being supplied to the downcomer. This problem has been particularly identified with respect to a certain type of bulk material feeder known as a gravimetric feeder. The gravimetric feeder includes a variable speed conveyor which may be designed to change speed in response to the amount of material being carried by the conveyor. In this respect, the conveyor speed may be increased or decreased to ensure that the desired amount of material is being moved by the conveyor. Manifestly, if the material is being unevenly transferred from the downcomer to the conveyor, the conveyor speed will necessarily have to adjust to accommodate for such fluctuations. The virtually continuous increase and decrease in conveyor speed presents numerous additional problems, including undue wear on the feeder components.
Those ordinarily skilled in the art will further appreciate that the downcomer on a gravimetric feeder traditionally includes a downstream discharge opening through which material is permitted to pass as it is moved along the path by the conveyor. In addition, the structure defining the discharge opening is designed to control the amount of material being transferred by the conveyor so as to facilitate relatively even and consistent volumetric transfer of material from the downcomer to the conveyor. This design, of course, assumes that sufficient material is being continuously deposited on the conveyor to cause the material that is moved out of the downcomer by the conveyor to be leveled off as it passes through the discharge opening. However, as will be set forth in further detail below, it has been determined that the traditional downcomer design simply does not permit the discharge opening to operate in the desired manner.
Another type of feeder that is susceptible to some of the aforementioned problems is a volumetric feeder. Such a feeder relies heavily on uniform and accurate volumetric flow and, contrary to a gravimetric feeder, includes no means for adjusting the belt speed in response to fluctuations in the volumetric flow rate.